In AWS A5.1, the electrodes listed include both low hydrogen and non-low hydrogen electrodes. In AWS D1.1-96, Group I steels may be welded with non-low hydrogen electrodes. This would include A36 steel. For Group II steels and higher, low hydrogen electrodes are required. These steels would include A572 grade 50. That means for welding on steels with minimum specified yield strengths exceeding 50 ksi, all electrodes should be of the low hydrogen type with specific coatings that are designed to be extremely low in moisture. Water, or H2O, will break down into its components hydrogen and oxygen under the intensity of the arc. This hydrogen can then enter into the weld deposit and may lead to unacceptable weld heat affected zone cracking under certain conditions. Low hydrogen electrodes have coatings comprised of materials that are very low in hydrogen.

The low hydrogen electrodes that
fit into the A5.1 classification include E7015, E7016, E7018, and E7028.

SI

NO.

Electrode

Classification

Properties

1.

E7015

Operate on DC only

2.

E7016

Operate on either AC or DC

3.

E7018

Operate on AC or DC and include
approximately 25% iron powder in their coatings; this increases the rate at
which metal may be deposited

4.

E7028

Contains approximately 50% iron
powder in the coating, enabling it to deposit metal at even higher rates.
However, this electrode is suitable for flat and horizontal welding only.

All the low hydrogen electrodes
listed in AWS A5.1 have minimum specified notch toughnesses of at least 20 ft.
lb. at 0°F. There are electrode classifications that have no notch toughness
requirements (such as E6012, E6013, E6014, E7024) but these are not low
hydrogen electrodes. Although there is no direct correlation between the low
hydrogen nature of various electrodes and notch toughness requirements, in the
case of SMAW electrodes in A5.1, the low hydrogen electrodes all have minimum
notch toughness requirements.

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Parag Traders in early 1980 in the GIDC of Vatva, Ahmedabad by Mr. Parag Mashruwala. We commence our business with the focus to cater to the requirement of Welding Electrodes, Equipments and Accessories to various industries specializing in Fabrication, Machine Shop, Forging and Castings in Ahmedabad.